In recent years, there has been an increasing demand for improved sensitivity and improved image quality in silver halide photographic materials.
In this regard, the internal latent image silver halide emulsions which are to be found in U.S. Pat. No. 3,979,213 (hereinafter referred to as document A), The Journal of Photoqraphic Science, Vol. 13, p. 48 (1965), ibid., Vol. 22, p. 174 (1974), ibid., Vol. 25, p. 19 (1977), ibid., Vol. 31, p. 41 (1986), Photographic Science and Engineering, Vol. 19, p. 333 (1975), U.S. Pat. Nos. 4,035,185 and 3,850,637, and in Berichte der Bunsengesellschaft for Physikalische Chemie, Vol. 67, p. 356 (1963) are outstanding in their color sensitization properties with markedly smaller intrinsic desensitization upon color sensitization than surface latent image emulsions, and additionally they are outstanding in the latent image storage properties since the latent image is formed inside the emulsion grain.
However, because the latent image-forming part lies deep within the emulsion grain at 0.01 .mu.m or more, development is inadequate with these internal latent image emulsions even when carrying out development processing with the developing solutions for black-and-white, color negative or color reversal photographic materials which are used in practice and it has not been possible to produce the optimum sensitivity/granularity ratio.
On the other hand, silver halide emulsions with a high silver iodide content (for example, 5 mol% or more) are excellent in their sensitivity and granularity, but the storage properties of the latent image are poor and they also have undesirable tendencies such as a lack of susceptibility to the interimage effect, particularly with color reversal materials, and there is a great desire for technical developments to supplement the disadvantages of such high iodide emulsions.
The interimage effect is described, for example, on pages 663 to 669 of Volume 42 of Journal of the Optical Society of America by Hanson et al., and on pages 106 to 118 and 246 to 255 of Volume 47 of Zeitschrift for Wissenschaftliche Photographic, Photophysique und Photochemie by A. Thiels.
There have been attempts to control the halogen composition within the grain in an endeavor to improve the color sensitization properties and the granularity. However, there have been no specific discussions as to what kind of halogen composition distribution is preferable within the grain or investigations into the internal and external halogen composition in the portion forming the latent image in internal latent image grains.